Abstract

We report a patient with human granulocytic anaplasmosis in South Korea. The patient had fever and thrombocytopenia. Human granulocytic anaplasmosis was confirmed by seroconversion, PCR, and sequence analysis for Anaplasma phagocytophilum. Morulae were observed in the cultured HL-60 cells inoculated with blood from the patient.

Anaplasma phagocytophilum, the causative agent of human granulocytic anaplasmosis (HGA), is a zoonotic tickborne pathogen transmitted by ixodid ticks that infects wild and domestic mammals and humans (1–3). HGA was first identified in the United States in 1994 (1) and subsequently in countries in Europe (3), China (4), and Japan (5).

To our knowledge, there is no report regarding the clinical description of HGA patients in South Korea. However,A. phagocytophilum has been detected in Haemaphysalis longicornis, Ixodes nipponensis, and I. persulcatus ticks (6,7) in this country. Molecular epidemiologic studies detected A. phagocytophilum in 2.6% (5/196) of striped field mice (7,8) and in 63.6% (42/66) of Korean water deer (9). Seroprevalence studies showed that 1.8% of serum samples from patients with acute fever were positive for A. phagocytophilum by an immunofluorescence antibody test (10). We report a patient with HGA and characterized the A. phagocytophilum isolate from this patient.

Dr Kye-Hyung Kim is an infectious disease physician and a senior researcher at Seoul National University College of Medicine, Seoul, South Korea. Her primary research interests are medical virology and emerging infectious diseases.